import java.util.Scanner;
class A extends shape
{
    public static void p(){
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入三角形的三边");
        double a = sc.nextInt();
        double b = sc.nextInt();
        double c = sc.nextInt();
        if ((a + b <= c) || (a + c <= b) || (b + c <= a)) {
            System.out.println("这不是三角形！");
        } else if (a == b && b == c) {
            System.out.println("这是正三角形！");
        } else if (a == b || b == c || a == c) {
            System.out.println("这是等腰三角形！");
        } else if (a * a == b * b + c * c || b * b == a * a + c * c || c * c == a * a + b * b) {
            System.out.println("这是直角三角形！");
        } else if ((a * a + b * b > c * c) || (a * a + c * c > b * b) || (b * b + c * c > a * a)) {
            System.out.println("这是锐角三角形！");
        } else if ((a * a + b * b < c * c) || (a * a + c * c < b * b) || (b * b + c * c < a * a)) {
            System.out.println("这是钝角三角形！");
        }
    }
}

public class shape {

    public static void main(String[] args) {
        A.p();
    }
}

